Capacitance of thin-film ferroelectrics under different drive signals.
IEEE Trans Ultrason Ferroelectr Freq Control
; 56(9): 1861-7, 2009 Sep.
Article
in En
| MEDLINE
| ID: mdl-19811989
ABSTRACT
Thin-film ferroelectric capacitance can be obtained by 2 different methods. Capacitance obtained using the derivative of its hysteresis loop is related to large applied signals and can be called the large-signal capacitance. Capacitance measured directly with a small, applied ac signal together with a slow changing dc bias is called the small-signal capacitance. This paper investigated the voltage dependence of the large- and small-signal capacitances. Measurements show that the large-signal C-V curve of thin-film ferroelectrics has much sharper peaks and higher peak values than the small-signal C-V curve. Analyses based on the Landau-Khalatnikov model shows that practical small-signal capacitance is closer to the ideal capacitance. However, its C-V curve has clearance areas around the coercive voltage, and the polarization switching is not reflected in the small-signal capacitance. This causes the peaks of small-signal C-V curves to be lower than that of large-signal C-V curves.
Full text:
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Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
IEEE Trans Ultrason Ferroelectr Freq Control
Journal subject:
MEDICINA NUCLEAR
Year:
2009
Document type:
Article
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